Background: The inability to perform liver resection is an important cause of high mortality in Hepatocellular carcinoma (HCC) patients. Based on the clinical data of anlotinib (a multi-targeted tyrosine kinase inhibitor) and tislelizumab (anti‐PD‐1 antibody) in HCC pts, we therefore evaluated the safety and efficacy of tislelizumab plus anlotinib as first-line therapy for patients with unresectable HCC. Methods: Patients aged 18-75 years, with unresectable HCC, ECOG PS 0-3, BCLC stage A-D, Child-Pugh score A-C, and CNLC stage Ia-IV were enrolled. Patients who met the inclusion criteria received tislelizumab(intravenous drip, 200 mg/d1, Q3W) and anlotinib(oral, 8-12 mg/d1-14, Q3W). The primary endpoint was objective response rate (ORR). The secondary endpoints included disease control rate (DCR),overall survival (OS), progression-free survival (PFS), adverse events (AEs), and serious adverse events (SAEs). Results: Between Sep-2020 until Sep-2022, 37 patients were enrolled, and 25 patients’ clinical data were available to assess clinical efficacy. The median age of the pts was 62 years (ranged 31-72 years), 15 pts (60%) ECOG PS 1, 14 pts (56%) BCLC stage C, 17 pts (68%) Hepatitis B Virus Infection and 13 pts (52%) had received prior local regional therapy. The ORR per mRECIST was 32% (95% CI, 12.3%-51.7%) and DCR was 72% (95% CI, 53.1%-90.9%). The best clinical response was CR in 2 pts (8%), 6 pts (24%) PR and 10 pts (40%) SD. With a median follow-up of 12.7 months, the estimated median PFS was 11.8 months, and the median OS was not reached. The most common AEs during follow-up were AST increased (52%), γ-GT increased (48%), and hypoalbuminemia (48%). Conclusions: Tislelizumab combined with anlotinib showed high antitumor activity and good tolerability in the treatment of unresectable HCC, which may be an effective and safe treatment option.